Circuit interrupter



"Ap y6, 1943. J.. w. HUFFSTUTTER f CIRCUIT INTERRUPIER4 Find Nov. 26,1941 Patented Apr. 6, .1943 n Westinghouse Electric & ManufacturingCompany, East Pittsburgh, Pa., a corporation oi' y Pennsylvania l yApplication November 26, 1941, Serial No. 420,514

11` claims.,r (ci. 20o-149) v l minal structure t is substantiallycylindrical in Thisinventionfrelates generally tov electric circuitinterrupters, and more specifically to inter-y rupters of the gas blasttype.

In interrupters which utilize a gas yblast generated by thearc forextinguishing the arc formed upon movement of one contact of thekinterrupter away from its cooperating contact, itis desirable that thegas exhaust take rplace longitudinallyof the arc so that the gases willpass through the entire arc length. In order to do this, itis necessarythat the hot ionized gases be Wards one of the contacts.

One object of'this invention is to provide a novel contact constructionfor circuit interrupters having relatively xed j and movable contacts,wherein lthe arc gases are directed through one directed toform, andls'provided with a transversely extendlng centrally apertured portion l2adapted to seat onthe end of insulating tube 2,y with the aperturethereof aligned rwith bore I0, and this parti-y tionalso serves tovretain washer-like members l within insulatingtube 2. f The end terminalstructure luis likewise provided with a 'transversely extendingapertured partition Il for recontact which is provided with means forshieldv ing it from the deleterious eiiects of such gases.A

Another object of this invention is to provide in an interrupter of the'typek described, a novel hollow ilxedcontact construction havingshielding means for protecting the contact from the arc and arc gases.g, f

These and other oblcts of this invention will become more apparentuponconsideration ofthe following detailed description of preferredembodiments thereof taken in connection withy the attached drawing, inwhich;

Figure 1 is a longitudinal, sectional view of` a circuit interrupterconstructed in accordance with this invention with the interruptercontacts shown in open circuit position, and

Fig. 2 is apartial sectional view of an interrupter similar to Fig. 1with the interruptor con- Xtacts shown in the closed circuit position,and with a modified form of control means for the contacts.

The circuit lnterrupter shown in Figs. 1 and 2 of the drawing ispreferably provided in a tu bular insulating housing 2,lwhich maybe ofany desired insulating material, such, for example, as fiber, asynthetic resin, or thelike. The insulating tube 2 has the opposite endsthereof threaded for threadedly receiving cap-like end terminalstructures 4 and 6, respectively. Interiorly of insulating tube 2 thereis preferably Lprovided a plurality of washer-like members 8 having acentral aperture therethrough, with the apertures of all the membersaligned to form a restricted arc bore I 0. The washer-like members 8`are preferablyof an insulating material which is capable of evolving anarc extinguishing Sas when in proximity to an electric arc, such, forexample, as boric acid, ber, a synthetic resin having this property, orthe like. The end ter- .taining washerlike members 8 within insulatingtube'y 2, and with the' aperture in the partition aligned with bore I0.

'I'he end terminal structure 6 is provided with` an intermediate,integral, transversely extending partition I5 having. a central aperturefor a purpose to be hereinafter reierredto, and adapted to support onopposite sides of this aperture contact fingers i8, pivoted as at I8 onthe partition. These pivoted contact fingers I6 provide the stationarycontact structure for the interrupter, and l they` are resilientlybiased towards each other and towardsV the central axis of therinterrupter by a coil compression rspring `2Il for each pivoted con'-tact I6, and positioned between the contact and the outer cylindricalwall ofterminal structure i. The pivoted contact fingers I6- areelectrically connected with terminal structure 6 by iiexible shunts 22which may be soldered or otherwise secured to the contactiingers and theside wall'of the terminal structure. The outer end wall ofy terminalstructure 6 is also provided with acentral aperture 24 which is alignedwith bore I0 and the aperturesk through partitions I2 and I5, forslidably receiving Athe outer end 26 cfa contact follower shield member.This shield member may be of rintegral construction, butr preferably,for assembly purposes, is made of two parts as shown, including an outerend portion 2B having an outwardly'flaring outlet passage 28therethrough, and an outwardly extending flange 29 ai; the inner endthereof, i and an inner end portion 30,

`threadedly engaged with outer portio'ny26 and adapted to be slidablymounted in the aperture in partition I5. lThe inner portion 30 of theshield is also provided with a central passage having an outwardlyilared entrance 32 which is aligned and communicates with ilared outletpassage 28. It will be noted that the follower shield is slidablymounted in aperture 24 and the aperture in vpartition wall I5, and acoil compression spring 34 is seated between the flange 29 of thefollower and the outer end wall of terminal structure lA so as tocontinually'bias the follower inwardly with' respect to the terminalhousing.v This inward movement of the follower ls limited by. engagementof ange 29 with partition I5, and the follower is movable outwardly fromthe position shown in Fig. l to that shown in Fig. 2, by engagement ofmovablel contact rod 36 therewith.

Movable contact rod 36 is adapted to be slidably mounted through arcbore I and through apertures in partition I4 and end wall 38 of terminalcap structure 4. The outer end of contact rod 36 is provided with anenlarged head portion 4U, and the contact rod is normally biasedoutwardly relative to insulating tube 2 by a coil compression spring 42seated between head 40 of the rod, and end wall 38 of terminal structure4.

The contact rod is adapted to be maintained in a closed circuit positionwherein the inner end thereof is positioned between contact fingers I6,by a slidable latch bar 44 movably mounted through the side wall ofterminal structure 4 and engageable in notch 50, formed adjacent theouter end of contact rod 36. The latch bar 44 is provided with a flange46 at the inner edge thereof, and a coil compression spring 48 seatedbetween. the flange 46 and side wall of terminal structure 4 is adaptedto continually bias the latch bar inwardly into engagement with contactrod 36. The outer end of latch bar 44 is pivotally connected to one armof a bell crank lever 52, and the other arm of the bell crank lever isprovided with a hook eye 54 for the reception of a hook-stick operatingmember or the like, for retracting the latch bar 44 from notch 50. Itwill also be noted that contact rod 36 is electrically connected toterminal structure 4 by means of a flexible shunt 66 secured to theterminal structure and the enlarged head 40 on the contact rod.

In the embodiment of the invention shown in Fig. 2, latch bar 44 isunder the control of bell crank lever 58, which, in turn, is pivoted tothe plunger rod 60 of a solenoid 62.

In the operation of the interruptor shown in Figs. l and 2, it will beobserved that in the closed circuit position shown in Fig. 2, thecircuit through the interrupter extends from terminal structure 6through flexible shunts 22, contact fingers I6, contact rcd 36, flexibleshunt 56 to terminal structure 4. It will also be observed that thecontact rod is maintained in the closed circuit position by engagementof latch bar 44 in notch 50, with operating spring 42 in a compressedcondition. Now, upon a circuit inter rupting operation caused bywithdrawal of. latch bar 44 from notch 5B, it will be apparent that theoperating spring 42 will then be free to move contact rod 36 downwardlyout of engagement with Contact fingers I6 and the arc will be drawn outin bore I0 where it is restricted and subjected to the action of thegases evolved from the material comprising washer-like members 8. Inorder that a blasting action of such cases may take G0 placelongitudinally through the entire extent of the are, and be exhaustedthrough the fixed contact structure, this structure, including thefollower shield 26, 30 is provided with the passages 32, 28 which ineffect form a Venturi outlet to aid in the blasting action. It will beobserved that as soon as contact rod 36 moves downwardly from theposition shown in Fig. 2. that it will be closelyr followed by thefollower shield moving under the influence of its spring 34.FurthermoreY but a relatively small movement of contact rod 36downwardly. will be required before contact fingers I6 arecompletelycovered by the inner portion 3i] of the follower shield, andsince the shield is of some good conducting material such, for example,as copper or a copper alloy, the arc will be transferred from thecontact fingers to the shield, and furthermore, the hot gases expelledfrom arc bore l0 will be prevented from contacting contact fingers I5,because the shield forms a passage independent of these contact fingers.

Obviously, by this construction the contact fingers I6 of the fixedcontact construction are not only protected from the deleterious effectsof arclng, but are also protected from the high temperature and highvelocity of the gases expelled from bore I0, which would cause excessiveerosion of the contact surfaces were it not for follower shield 26, 30.This erosion of contacts I6, as well as deposits of material thereonfrom gases evolved, would obviously result in a very poor contactbetween contact fingers I6 and contact rod 36 when the lnterrupter wasreclosed. With the construction described above, the fixed contactfingers I4 are entirely protected from the effects of the arc and hotgases expelled, while at the same time an outlet is provided through thefixed contact construction for the arc gases in novel manner.

In the embodiment of the invention shown in Fig. l, latch bar 44 isreadily released to effect a circuit interrupting operation by merelypulling downwardly on hook eye 64. In the embodiment shown in Fig. 2 ofthe drawing, latch bar 44 is adapted to be released by energization 0fsolenoid 62, and this may be remotely controlled, or the solenoid maybeconnected in the interrupter circuit so as to be responsive topredetermined electrical conditions to effect a circuit interruptingoperation of the interruptor.

After a circuit interrupting operation, it is obvious that the circuitmay be reclosed by moving contact rod 36 upwardly from the positionshown in Fig. 1, for example, as by a force exerted on the flanged head4I) thereof. In its upward movement, the contact rod will first engagethe inner end of inner portion 30 of the follower shield and thereaftercause movement of the shield upwardly while the inner end of the contactrod moves between contact fingersl I6 to the position shown in Fig. 2 ofthe drawing, wherein the circuit through the interrupter isreestablished.

From the foregoing it is believed to be readily apparent that thecircuit interrupter herein disclosed is provided with a novel fixedcontact construction embodying a follower shield means capable of notonly protecting the fixed contacts from arcing, but also providing apassage for gases expelled during interruption, while protecting thenxed contacts from the deleterious effects of such gases. It is alsoapparent that this invention provides a hollow contact construction withhollow shielding follower means assoclated therewith providing a gaspassageway therethrough of optimum design, and which is automaticallyoperable upon a circuit interrupting operation to shield and protect thecontact from arcing and from the hot gases expelled.-

Having described preferred embodiments of the invention in accordancewith the patent statutes, it should be understood that the invention isnot to be limited to the particular embodiments herein described,inasmuch as it will be obvious, particularly to those skilled in the artthat many changes and modifications may be -made in these particularembodiments without departing from the broad spirit and scope of thisinvention. Thus, for example, although the interruptor is shown for usewith substantially circular contacts, it is apparent that contactshaving other cross-sectionalfforms can be readily used with thisinvention. Therefore, it is desired that the invention be interpreted asbroadly as possible in view of the prior art.

I claim as my invention: k

l.' In a circuit interrupter, separable contacts one of which is tubularto receive'the other in closed circuit position and to vent the arcgases formed when said contacts separate, and tubular shielding meanstelescopically engaged with said one contact and automatically movablein response to separation of said contacts to a shielding position withrespect to said one contact.

2. In a circuit interrupter, separable contacts one oi' which is tubularto receive the other in closed circuit position and to vent the arcgases formed when said contacts separate, and tubular shielding means`of conducting material telescopically engaged with said one contact andautomatically movable in response to separation of said contacts to ashielding position with respect to said one contact and to a positioncloser to said other contact than said one contact so that the arc drawnwill be transferred to said shielding means.

3. In a circuitinterrupter, relatively xed and movable contact means,said fixed contact being tubular to receive said movable contact inclosed circuit position and to vent the arc gases formed when saidmovable contact is moved away from said fixed contact, and a tubularshielding means adapted for telescoping movement in said fixed contactin response to movement of said movable contact away from said fixedcontact to shield the inner wall of said fixed contact from thedeleterious effects of said arc gases.

4. In a circuit interrupter, relatively fixed and movable contact means,said fixed contact being tubular to receive said movable contact inclosed circuit position and to vent the arc gases formed when saidmovable contact is moved away from said fixed contact, tubular shieldingmeans adapted for telescoping movement in said fixed contact in responseto movement oi' said movable contact away from said iixed contact toshield the inner wall of said fixed contact from the deleterious eiectsof said arc gases, and said shielding means having a flared outlet.

5. In a circuit interruptor, relatively fixed and movable contact means,said xed contact being tubular to receive said movable contact in closedcircuit position and to vent the arc gases formed when said movable'contact is moved away from said fixed contact, tubular shielding meansof conducting material adapted i'or telescoping movement in said fixedcontact in response to movement of said movable contact away from saidfixed contact to shield the inner wall oi said fixed contact from thedeleterious effects of said arc gases, and to a position closer to saidother CII contact said shielding means will follow to shield said fixedcontact from the arc gases, and stop means for preventing such followingkmovement of said shielding means substantially beyond its shieldingposition.

7. Inv a circuit interrupter, a tubular casing of insulating materialhaving an. open end, spaced terminals on said casing, interrupting meansin said casing including a tubular contact means adjacent said open endof the casing, and a rod-like contact movably mounted. longitudinally ofsaid casing, said contacts electri-r l cally connected to saidterminals, respectively,

means of insulating material in said casing forming a restricted arcpassage in which said rod-likecontact is adapted to move, at least innerWall portions of said passage being of a material capable of evolving anarc extinguishing gas when in proximity to an electric arc,

arc gases, separable contacts in said chamber,

one of which is positioned in the path of gases escaping from said ventwhen the circuit is interrupted, and shielding means movable in responseto separation of said contacts to a position for shielding said onecontact from the deleterious effects of said gases.

9. In a circuit interrupter, means forming an arc chamber having anopening for venting the arc gases, separable contacts in said chamber,

contact than said one contact so that the arc t one of which ispositioned in the path of gases escaping from said vent when the circuitis interrupted, and shielding means of conducting material associatedwith said one contacty and movable in responseto separation of saidcontacts to a positionfor shielding said one contact from thedeleterious effects of said gases for relieving said one contact ofarcing.

10. In a circuit interrupter, means forming an arc chamber having anopening for venting the arc gases, separable contacts in said chamber,one of which is positioned in the path oi' gases escaping from said ventwhen'the circuit is interrupted, and tubular shielding means movableaxially of said opening to a position shielding said one contact fromthe arc gases and providing a passage for saidgases axially to said ventopening. f

11. In a circuit interruptor, means forming an arc chamber having anopening for venting the arc gases, separable contacts in said chamber,one of 'which is positioned in the path of gases escaping front saidvent when the circuit is interrupted, tubular shielding means normallypositioned in said vent opening and substantially filling the same, withat least a portion thereof projecting outwardly through said ventopening, means moving said shielding means into said chamber kinresponse to separation oi' said contacts to a position shielding saidone contact, and means limitinginward movement of said shielding mea-nsso that a portion thereof remains in said vent opening to conduct thearc gases therethrough,

VJOHN W. HUrrsTUTrEr-t.

